Two-dimensional control of surface plasmons and directional beaming from arrays of subwavelength apertures

We demonstrate two-dimensional control of coherent modes of surface plasmons (SP) in a metallic array of subwavelength apertures. SP mode intensity and propagation direction is manipulated by varying the wavelength, incidence angle, and polarization of the excitation photons. We also demonstrate directional beaming of light from this device. Finite-difference-time-domain simulations of the SP modes closely resemble the observations by near-field scanning optical microscopy. Calculated SP coupling efficiencies and transmission are also presented.